package org.apache.solr.search.grouping.endresulttransformer;

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import org.apache.lucene.search.ScoreDoc;
import org.apache.lucene.search.grouping.GroupDocs;
import org.apache.lucene.search.grouping.TopGroups;
import org.apache.solr.common.SolrDocumentList;
import org.apache.solr.common.util.NamedList;
import org.apache.solr.common.util.SimpleOrderedMap;
import org.apache.solr.handler.component.ResponseBuilder;
import org.apache.solr.schema.FieldType;
import org.apache.solr.schema.SchemaField;
import org.apache.solr.search.SolrIndexSearcher;
import org.apache.solr.search.grouping.distributed.command.QueryCommandResult;

import java.util.ArrayList;
import java.util.List;
import java.util.Map;

/**
 * Implementation of {@link EndResultTransformer} that keeps each grouped result
 * separate in the final response.
 */
public class GroupedEndResultTransformer implements EndResultTransformer {

	private final SolrIndexSearcher searcher;

	public GroupedEndResultTransformer(SolrIndexSearcher searcher) {
		this.searcher = searcher;
	}

	/**
	 * {@inheritDoc}
	 */
	public void transform(Map<String, ?> result, ResponseBuilder rb,
			SolrDocumentSource solrDocumentSource) {
		NamedList<Object> commands = new NamedList<Object>();
		for (Map.Entry<String, ?> entry : result.entrySet()) {
			Object value = entry.getValue();
			if (TopGroups.class.isInstance(value)) {
				@SuppressWarnings("unchecked")
				TopGroups<String> topGroups = (TopGroups<String>) value;
				NamedList<Object> command = new SimpleOrderedMap<Object>();
				command.add("matches", rb.totalHitCount);
				if (topGroups.totalGroupCount != null) {
					command.add("ngroups", topGroups.totalGroupCount);
				}

				List<NamedList> groups = new ArrayList<NamedList>();
				SchemaField groupField = searcher.getSchema().getField(
						entry.getKey());
				FieldType groupFieldType = groupField.getType();
				for (GroupDocs<String> group : topGroups.groups) {
					SimpleOrderedMap<Object> groupResult = new SimpleOrderedMap<Object>();
					if (group.groupValue != null) {
						groupResult.add("groupValue", groupFieldType
								.toObject(groupField.createField(
										group.groupValue, 0.0f)));
					} else {
						groupResult.add("groupValue", null);
					}
					SolrDocumentList docList = new SolrDocumentList();
					docList.setNumFound(group.totalHits);
					if (!Float.isNaN(group.maxScore)) {
						docList.setMaxScore(group.maxScore);
					}
					docList.setStart(rb.getGroupingSpec().getGroupOffset());
					for (ScoreDoc scoreDoc : group.scoreDocs) {
						docList.add(solrDocumentSource.retrieve(scoreDoc));
					}
					groupResult.add("doclist", docList);
					groups.add(groupResult);
				}
				command.add("groups", groups);
				commands.add(entry.getKey(), command);
			} else if (QueryCommandResult.class.isInstance(value)) {
				QueryCommandResult queryCommandResult = (QueryCommandResult) value;
				NamedList<Object> command = new SimpleOrderedMap<Object>();
				command.add("matches", queryCommandResult.getMatches());
				SolrDocumentList docList = new SolrDocumentList();
				docList.setNumFound(queryCommandResult.getTopDocs().totalHits);
				if (!Float.isNaN(queryCommandResult.getTopDocs().getMaxScore())) {
					docList.setMaxScore(queryCommandResult.getTopDocs()
							.getMaxScore());
				}
				docList.setStart(rb.getGroupingSpec().getGroupOffset());
				for (ScoreDoc scoreDoc : queryCommandResult.getTopDocs().scoreDocs) {
					docList.add(solrDocumentSource.retrieve(scoreDoc));
				}
				command.add("doclist", docList);
				commands.add(entry.getKey(), command);
			}
		}
		rb.rsp.add("grouped", commands);
	}

}
